1. Field of the Invention
The present invention relates to a communication system for users of portable hearing aids of the type having at least a microphone and/or a telephone coil as an input transducer, an amplifier for amplifying the electrical signals of the input transducer, a signal processing circuit with memory, and an earpiece as an output transducer.
2. Description of the Prior Art
Hearing aids of this type are equipped with digital or analog signal processing circuitry. In digital hearing aids, there is a digital signal processor in which the signal processing takes place, using a digital signal processing program whose contents are loaded into the hearing aid. As a result, in a digital hearing aid, the details of the acoustical processing can be modified by modifying the program stored in the memory, and thus it is simple to perform an adjustment to optimize the speech intelligibility for an individual patient.
Specifically for telephone use, besides the microphone, hearing aids are equipped with a telephone coil or induction coil, as well as a change-over switch which must be operated to change from microphone mode to telephone coil mode. Because users of hearing aids have problems using mobile telephones, German Utility Model 29 608 340 teaches a communication system for hearing aid users for use in connection with a mobile telephone.
In order to simplify the handling of small hearing aid devices worn on the head, German OS 44 19 901, corresponding to U.S. Pat. No. 5,636,285, teaches a hearing aid device without manual engagement or means of activation. In this hearing aid device, the handling (switching on/off; setting louder/quieter; selecting a program which fits a hearing/environmental situation) or the control of a component which affects the transmission characteristic of the amplifier, occurs by recognition and evaluation of a code word spoken by the hearing aid user.